On a data center network, service processing based on open systems interconnection (OSI) layer 4 to layer 7 usually needs to be performed on a packet flow. For example, service processing generally includes: providing processing of a firewall, network address translation (NAT), home control, and the like. Different service processing may need to be provided for different packet flows. In addition, generally, not one type of service processing is performed on a packet flow, but multiple types of service processing need to be provided for the packet flow. For example, firewall processing and NAT processing may need to be performed on some packet flows, and firewall processing and home control processing may be expected for some other packet flows. In this case, how to implement service processing on a packet flow is an issue to be resolved.